MINOR: mux_quic: implement qstrm rx buffer realign

The previous patch defines a new QCC buffer member to implement QMux
reception. This patch completes this by perfoming realign on it during
qcc_qstrm_recv(). This is necessary when there is not enough contiguous
data to read a whole frame.

diff --git a/src/mux_quic_qstrm.c b/src/mux_quic_qstrm.c
index 67632b1f316a77255fbe88d7bbbb4f86327e9ddd..25bd37ea6efa31b1d10932003a2eea87917939bd 100644 (file)
--- a/src/mux_quic_qstrm.c
+++ b/src/mux_quic_qstrm.c
@@ -96,16 +96,41 @@ int qcc_qstrm_recv(struct qcc *qcc)
        TRACE_ENTER(QMUX_EV_QCC_RECV, qcc->conn);
 
        do {
-               b_realign_if_empty(buf);
+ recv:
+               /* Wrapping is not supported for QMux reception. */
+               BUG_ON(b_data(buf) != b_contig_data(buf, 0));
+
+               /* Checks if there is no more room before wrapping position. */
+               if (b_head(buf) + b_contig_data(buf, 0) == b_wrap(buf)) {
+                       if (!b_room(buf)) {
+                               /* TODO frame bigger than buffer, connection must be closed */
+                               ABORT_NOW();
+                       }
+
+                       /* Realign data in the buffer to have more room. */
+                       memmove(b_orig(buf), b_head(buf), b_data(buf));
+                       buf->head = 0;
+               }
+               else {
+                       /* Ensure maximum room is always available. */
+                       b_realign_if_empty(buf);
+               }
+
                ret = conn->xprt->rcv_buf(conn, conn->xprt_ctx, buf, b_contig_space(buf), NULL, 0, 0);
                BUG_ON(conn->flags & CO_FL_ERROR);
 
                total += ret;
                while (b_data(buf)) {
                        frm_ret = qstrm_parse_frm(qcc, buf);
+
                        BUG_ON(frm_ret < 0); /* TODO handle fatal errors */
-                       if (!frm_ret)
+                       if (!frm_ret) {
+                               /* Checks if wrapping position is reached, requires realign. */
+                               if (b_head(buf) + b_contig_data(buf, 0) == b_wrap(buf))
+                                       goto recv;
+                               /* Truncated frame read but room still left, subscribe to retry later. */
                                break;
+                       }
 
                        b_del(buf, frm_ret);
                }